At least 400 children have been killed in 11 months of violence in Syria and almost the same number detained, with reports of torture and sexual abuse, the United Nations Children's Fund said Tuesday.
"As of the end of January, 400 children are dead and more than 400 have been detained," UNICEF spokeswoman Marixie Mercado said at a briefing.
"There are reports of children arbitrarily arrested, tortured and sexually abused while in detention," the agency added in a statement.
Mercado said the figures for children killed came from Syrian human rights groups "that we find to be credible".
UNICEF said heavy shelling of civilian neighbourhoods in the city of Homs "was undoubtedly causing further suffering for more children."
"This must stop," said executive director Anthony Lake in a statement. "Even one child killed in the violence is one child too many."
Lake urged the Syrian authorities "to allow help to all those who need it desperately".
The relief agency said it did not have access to affected areas of Homs and was not able to confirm the impact of the attacks.
But it had "credible reports, including from international media inside Homs, that children are caught in the violence".
Syrian rights groups say hundreds of people have been killed in Homs and its environs after government troops launched a wave of massive assaults over the past few days.
According to rights groups, more than 6,000 people have died nationwide since the outbreak of the revolt against Assad's regime in mid-March.